矿山不同片区土壤中Zn、Pb、Cd、Cu和As的污染特征

根据某典型有色金属矿山生产过程的污染状况,将受污染的矿区土壤分为尾矿污染区、坑道废水污染区、污风降尘污染区和精矿运输污染区4种类型.选择该矿区受污染土壤样本28个,用等离子体原子发射光谱仪(ICP-AES)等方法分析了土壤重金属含量和形态特征.结果表明,该矿区土壤重金属Zn、Pb、Cd、Cu和As污染较为严重,土壤Zn、Pb、Cd、Cu和As平均含量分别达508.6mg·kg^-1、384.8mg·kg^-1、7.53mg·kg^-1、356mg·kg^-1 和44.6mg·kg^-1.不同片区间存在明显差别,污染强度以尾矿污染区最高,内梅罗综合指数为173,其次是精矿运输污染区和坑道废水污染区,污风降尘污染区污染较轻;各片区土壤的重金属元素以残余态为主,有机结合态比例最小,不同元素之间、不同片区土壤之间各形态所占比例差别不大.

Polluted Characteristics of Zn, Pb, Cd, Cu and As in Soil of Different Mining Activity Zones

Depending upon the polluted features of various mining activities in a typical nonferrous metal mine, the contaminated soil area was divided into four zones which were polluted by tailings, mine drainage, dust deposition in wind and spreading minerals during vehicle transportation respectively. In each zone, soil samples were collected. Total 28 soil samples were dug and be analyzed by ICP-AES and other relevant methods. The results indicated that the average contents of Zn, Pb, Cd, Cu and As in soils were 508.6 mg·kg^-1, 384.8mg·kg^-1, 7.53mg·kg^-1, 356mg·kg^-1 and 44.6mg·kg^-1 respectively. But the contents of heavy metals in different zone have distinct differences. The pollution intension of tailing was the heaviest which Nemero index was 17.3. Ranking of pollution intension of different zones from heavy to light is in the sequence of tailing zone, mineral transportation zone, mine drainage zone, and dust deposition zone. The original phase of heavy metals and minerals is the main pollution ingredient of each zone. The proportion of oxidizing association with organic substance is small. Difference of the association of heavy metals is small in different polluted zones.